40 MD musculardevelopment.com July 2019
By Steve Blechman and Thomas Fahey, Ed.D.Drugs CUTTING-EDGE RESEARCH
Best Dosing Strategy for GH
Growth hormone (GH) replacement therapy is very popular with many
older adults and bodybuilders because it increases muscle mass, decreases
body fat, increases exercise capacity and makes people feel bett er. Studies
usually administer drugs in proportion to bodyweight. This can be confusing
and people react diff erently to drugs, so this method lacks fl exibility. Another
method is to administer increasing doses gradually. Stanford University
researchers found no diff erence in eff ects when administering the drugs
according to bodyweight or set levels based on desired eff ects. In six months,
subjects (average age 48) gained 7 pounds of lean mass; decreased fat by 2
percent (actual percentage); lost abdominal fat; and showed favorable changes
in blood pressure, cholesterol and LDL (bad cholesterol). About 17 percent of the
subjects experienced edema (swelling) from GH treatment, but otherwise side
eff ects were mild or non-existent. Growth hormone replacement therapy is safe
and eff ective, provided the dose is matched against desired results and side
eff ects. (J Clin Endocrinol Metab, 89: 3224-3233)Testosterone Builds Muscle
and Cuts Fat
Early studies on anabolic steroids suggested that the
drugs didn’t work and they produced deadly side eff ects.
Consequently, the use of testosterone and testosterone-
like drugs are banned from almost all sports. The truth
is that the drugs work and the side eff ects are usually
minor and reversible.
Much of what we know
about testosterone
supplements in
men comes from Dr.
Shalender Bhasin and
colleagues at UCLA.
In a series of elegant
studies, they found
that muscles grow
and fat decreases in
proportion to blood
levels of testosterone
(particularly free
testosterone).
Testosterone triggers
the development of satellite cells in muscles that result
in more cell nuclei per muscle cell. Cells store genetic
material in the nucleus, which directs the cells to make
new protein. Increasing the number of nuclei in a muscle
cell makes it easier to produce new muscle protein,
which assists in the development of muscle size and
strength. Testosterone also increases the size of motor
nerves, which explains the increase in power commonly
experienced by many athletes. These fi ndings are
particularly interesting for older adults who experience
muscle and nerve deterioration and increased body fat
with age. (Curr Opin Clin Nutr Metab Care, 7: 271-277)Modafinil (Provigil)
Improves Endurance
Modafi nil, sold in the United States as Provigil, is a mild stimulant used
to treat narcolepsy (daytime sleepiness) and hypersomnia (feeling sleepy
all the time). Students and workaholics have latched onto the drug as a
way to increase focus while working, studying or taking exams. Modafi nil
was added to the World Anti-Doping Agency’s “Prohibited List” in 2004, but
evidence that it improves performance is mainly theoretical. Canadian military
researchers found that modafi nil helped healthy males increase endurance on
a stationary bike by 15 to 20 percent. Also, the perception of eff ort during the
exercise tests was less in the drug group than in the control group. Modafi nil
provides a signifi cant boost to performance, probably because the drug reduced
the sensation of fatigue. Some physicians think Provigil may become the next
pop drug (like Viagra) because of its eff ects on mental concentration and work
capacity. (Med Sci Sports Exerc 36: 1078-1082)
The German Super Boy
Myostatin is a chemical controlled by the myostatin gene that inhibits muscle
growth. Scientists have perfected a technique to inhibit the gene in catt le, mice
and fi sh that has made these animals much larger than normal. Germany
researchers studied a boy with a mutant myostatin gene who had muscles
twice the size of normal children, which shows the potential for myostatin
manipulations in humans. Scientists fi rst examined the boy when he was a
newborn and noticed his unusually large leg and arm muscles. The boy’s
muscles were twice as large as expected at age 4. The boy’s family members
were also unusually strong. His mother had been a professional athlete. She
had a mutated myostatin gene, while the child had mutations in two genes
involved in myostatin production. The boy had normal levels of testosterone and
insulin-like growth factor (IGF-1), which showed that his unusual muscle size was
due to low levels of myostatin. The research showed that suppressing myostatin
could be the key to promoting muscle growth in humans, information that could
be helpful for treating people with muscle-wasting diseases. Athletes may use
any potential treatments for developing muscles for non-medical uses. We
don’t know the long-term consequences of myostatin suppression. The benefi ts
outweigh the potential risks in an incurable disease such as muscular dystrophy,
but that’s not the case for athletes trying to develop large muscles. Most likely,
bodybuilders and power athletes will use gene-suppressing techniques to
promote muscle growth, even though there might be negative consequences. (N
Engl J Med, 350: 2682-2688; N Engl J Med, 350: 2642-2644)